romains.py

Created on March 22, 2020

730 Bytes

Chiffres romains vers chiffres arabes et inversement.

def a2r(n):
  if n not in range(1,5000):
    raise ValueError("Entre 1 et 4999.")
  chiffres=["I","V","X","L","C","D"]
  r=""
  for i in range(3):
    n,u=divmod(n,10)
    if u in range(1,4):
      r=chiffres[2*i]*u+r
    elif u==4:
      r=chiffres[2*i]+chiffres[2*i+1]+r
    elif u in range(5,9):
      r=chiffres[2*i+1]+chiffres[2*i]*(u-5)+r
    elif u==9:
      r=chiffres[2*i]+chiffres[2*i+2]+r
  return "M"*n+r

def r2a(c):
  valeurs={"M":1000,"D":500,"C":100,"L":50,"X":10,"V":5,"I":1,"\n":0}
  liste=[valeurs[i] for i in c]
  for i in range(len(c)-1):
    if liste[i]<liste[i+1]:
      liste[i]*=-1
  resultat=sum(liste)
  if a2r(resultat)==c:
    return resultat
  raise ValueError("Nombre mal construit.")